Commit 6d591c46 authored by Linus Walleij's avatar Linus Walleij

tools/gpio: create GPIO tools

This creates GPIO tools under tools/gpio/* and adds a single
example program to list the GPIOs on a system. When proper
devices are created it provides this minimal output:

Cc: Johan Hovold <johan@kernel.org>
Cc: Michael Welling <mwelling@ieee.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 3c702e99
......@@ -4820,6 +4820,7 @@ F: include/linux/gpio/
F: include/linux/gpio.h
F: include/asm-generic/gpio.h
F: include/uapi/linux/gpio.h
F: tools/gpio/
GRE DEMULTIPLEXER DRIVER
M: Dmitry Kozlov <xeb@mail.ru>
......
......@@ -13,6 +13,7 @@ help:
@echo ' cpupower - a tool for all things x86 CPU power'
@echo ' firewire - the userspace part of nosy, an IEEE-1394 traffic sniffer'
@echo ' freefall - laptop accelerometer program for disk protection'
@echo ' gpio - GPIO tools'
@echo ' hv - tools used when in Hyper-V clients'
@echo ' iio - IIO tools'
@echo ' lguest - a minimal 32-bit x86 hypervisor'
......@@ -53,7 +54,7 @@ acpi: FORCE
cpupower: FORCE
$(call descend,power/$@)
cgroup firewire hv guest spi usb virtio vm net iio: FORCE
cgroup firewire hv guest spi usb virtio vm net iio gpio: FORCE
$(call descend,$@)
liblockdep: FORCE
......@@ -119,7 +120,7 @@ acpi_clean:
cpupower_clean:
$(call descend,power/cpupower,clean)
cgroup_clean hv_clean firewire_clean lguest_clean spi_clean usb_clean virtio_clean vm_clean net_clean iio_clean:
cgroup_clean hv_clean firewire_clean lguest_clean spi_clean usb_clean virtio_clean vm_clean net_clean iio_clean gpio_clean:
$(call descend,$(@:_clean=),clean)
liblockdep_clean:
......@@ -155,6 +156,7 @@ build_clean:
clean: acpi_clean cgroup_clean cpupower_clean hv_clean firewire_clean lguest_clean \
perf_clean selftests_clean turbostat_clean spi_clean usb_clean virtio_clean \
vm_clean net_clean iio_clean x86_energy_perf_policy_clean tmon_clean \
freefall_clean build_clean libbpf_clean libsubcmd_clean liblockdep_clean
freefall_clean build_clean libbpf_clean libsubcmd_clean liblockdep_clean \
gpio_clean
.PHONY: FORCE
CC = $(CROSS_COMPILE)gcc
CFLAGS += -Wall -g -D_GNU_SOURCE
all: lsgpio
lsgpio: lsgpio.o gpio-utils.o
%.o: %.c gpio-utils.h
.PHONY: clean
clean:
rm -f *.o lsgpio
/*
* GPIO tools - helpers library for the GPIO tools
*
* Copyright (C) 2015 Linus Walleij
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#include "gpio-utils.h"
/*
* GPIO tools - utility helpers library for the GPIO tools
*
* Copyright (C) 2015 Linus Walleij
*
* Portions copied from iio_utils and lssio:
* Copyright (c) 2010 Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
* Copyright (c) 2008 Jonathan Cameron
* *
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#ifndef _GPIO_UTILS_H_
#define _GPIO_UTILS_H_
#include <string.h>
static inline int check_prefix(const char *str, const char *prefix)
{
return strlen(str) > strlen(prefix) &&
strncmp(str, prefix, strlen(prefix)) == 0;
}
#endif /* _GPIO_UTILS_H_ */
/*
* lsgpio - example on how to list the GPIO lines on a system
*
* Copyright (C) 2015 Linus Walleij
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* Usage:
* lsgpio <-n device-name>
*/
#include <unistd.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdio.h>
#include <dirent.h>
#include <errno.h>
#include <string.h>
#include <poll.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/ioctl.h>
#include <linux/gpio.h>
#include "gpio-utils.h"
int list_device(const char *device_name)
{
struct gpiochip_info cinfo;
char *chrdev_name;
int fd;
int ret;
ret = asprintf(&chrdev_name, "/dev/%s", device_name);
if (ret < 0)
return -ENOMEM;
fd = open(chrdev_name, 0);
if (fd == -1) {
ret = -errno;
fprintf(stderr, "Failed to open %s\n", chrdev_name);
goto free_chrdev_name;
}
/* Inspect this GPIO chip */
ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo);
if (ret == -1) {
ret = -errno;
fprintf(stderr, "Failed to retrieve GPIO fd\n");
if (close(fd) == -1)
perror("Failed to close GPIO character device file");
goto free_chrdev_name;
}
fprintf(stdout, "GPIO chip: %s, %u GPIO lines\n",
cinfo.name, cinfo.lines);
if (close(fd) == -1) {
ret = -errno;
goto free_chrdev_name;
}
free_chrdev_name:
free(chrdev_name);
return ret;
}
void print_usage(void)
{
fprintf(stderr, "Usage: lsgpio [options]...\n"
"List GPIO chips, lines and states\n"
" -n <name> List GPIOs on a named device\n"
" -? This helptext\n"
);
}
int main(int argc, char **argv)
{
const char *device_name;
int ret;
int c;
while ((c = getopt(argc, argv, "n:")) != -1) {
switch (c) {
case 'n':
device_name = optarg;
break;
case '?':
print_usage();
return -1;
}
}
if (device_name)
ret = list_device(device_name);
else {
const struct dirent *ent;
DIR *dp;
/* List all GPIO devices one at a time */
dp = opendir("/dev");
if (!dp) {
ret = -errno;
goto error_out;
}
ret = -ENOENT;
while (ent = readdir(dp), ent) {
if (check_prefix(ent->d_name, "gpiochip")) {
ret = list_device(ent->d_name);
if (ret)
break;
}
}
ret = 0;
if (closedir(dp) == -1) {
perror("scanning devices: Failed to close directory");
ret = -errno;
}
}
error_out:
return ret;
}
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